Lens-fitted photo film unit provided with a stop-changing mechanism, and device for changing a stop

Abstract

A first pin to be used for rotatably supporting a shutter blade is disposed near a second pin to be used for rotatably supporting a stop-changing plate. A rotational direction of the shutter blade from a closed position to an open position is set so as to be identical with a rotational direction of the stop changing plate directing from a smaller-stop position to a larger-stop position. Rotational spaces of the shutter blade and the stop changing plate are arranged at one side of a photographic optical axis so that a protrusion of a front cover for containing them is prevented from enlarging.

What is claimed is:  
     
       1. A lens-fitted photo film unit comprising: 
       a taking lens including at least a front lens and a rear lens;  
       a larger-stop plate provided with a larger stop and disposed at either of positions, one of which is between the front and rear lenses and the other of which is behind the rear lens;  
       a shutter blade being rotatable between a closed position where an exposure aperture is closed, and an open position where the exposure aperture is opened; and  
       a stop-changing plate being rotatable between a smaller-stop position where a smaller stop is inserted into an interval of the front and rear lenses, and a larger-stop position where the smaller stop is evacuated from the interval of the front and rear lenses,  
       wherein rotational centers of said shutter blade and said stop-changing plate are arranged in either state of coincidence and approximation, and a rotational direction of the shutter blade from the closed position to the open position is set to be identical with a rotational direction of the stop-changing plate from the smaller-stop position to the larger-stop position.  
     
     
       2. A lens-fitted photo film unit according to  claim 1 , further comprising: 
       a changeover ring attached to a periphery of a lens barrel containing said taking lens, said changeover ring rotating in accordance with a stop-changing operation to rotate said stop-changing plate between the smaller-stop position and the larger-stop position in association with a rotation of said changeover ring.  
     
     
       3. A lens-fitted photo film unit according to  claim 2 , further comprising: 
       a shutter-speed changing mechanism for changing a shutter speed by regulating a rotational range of said shutter blade, said shutter-speed changing mechanism changing the shutter speed in association with the rotation of the changeover ring.  
     
     
       4. A lens-fitted photo film unit according to  claim 3 , wherein said shutter-speed changing mechanism changes the shutter speed from high speed to low speed when said stop-changing plate is set from the larger-stop position to the smaller-stop position. 
     
     
       5. A lens-fitted photo film unit according to  claim 4 , further comprising: 
       a synchro switch pushed and curved by a part of said shutter blade when said shutter blade rotates from the closed position toward the open position, said synchro switch being kept in an ON-state while curving,  
       wherein said shutter-speed changing mechanism changes a curve amount of said synchro switch, which is caused by said shutter blade, in two steps in order to set the shutter speed at the high speed and the low speed.  
     
     
       6. A lens-fitted photo film unit according to claim  5 , wherein said shutter-speed changing mechanism includes a pad movable behind the synchro switch, said pad being positioned behind the synchro switch to decrease the curve amount of the synchro switch caused by the shutter blade when the shutter speed is the high speed, and said pad being evacuated from the back of the synchro switch to increase the curve amount of the synchro switch when the shutter speed is the low speed. 
     
     
       7. A lens-fitted photo film unit according to  claim 6 , further comprising: 
       a protrusion formed on the front of said lens-fitted photo film unit to contain said taking lens, said stop-changing plate being contained in said protrusion.  
     
     
       8. A lens-fitted photo film unit according to  claim 4 , wherein said stop-changing plate has a V-figure shape, and one end thereof is formed with the smaller stop. 
     
     
       9. A lens-fitted photo film unit according to  claim 8 , wherein the other end of said stop-changing plate is formed with an ellipse hole with which a link pin provided on said changeover ring engages. 
     
     
       10. A lens-fitted photo film unit according to  claim 9 , wherein said ellipse hole curves in an L-figure shape. 
     
     
       11. A lens-fitted photo film unit according to  claim 4 , wherein said lens barrel is provided with a cut portion through which said stop-changing plate rotates. 
     
     
       12. A lens-fitted photo film unit according to  claim 11 , further comprising: 
       a spacer disposed between the front and rear lenses to secure a rotational space of said stop-changing plate.  
     
     
       13. A lens-fitted photo film unit according to  claim 12 , wherein said spacer is formed with a fixed opening bigger than said larger stop of said larger-stop plate. 
     
     
       14. A lens-fitted photo film unit according to  claim 13 , wherein said spacer has a concave portion, a part of said stop-changing plate entering said concave portion when said stop-changing plate is set to the smaller-stop position. 
     
     
       15. A lens-fitted photo film unit according to  claim 14 , wherein said spacer is disposed in front of said larger-stop plate. 
     
     
       16. A lens-fitted photo film unit according to  claim 15 , wherein said fixed opening is formed at a central portion of said spacer. 
     
     
       17. A lens-fitted photo film unit according to  claim 16 , wherein said larger-stop plate and said spacer are unified.